Field of the Invention
The invention relates to a phase compensating apparatus, and more particularly to the phase compensating apparatus for adjusting phase of a transmission signal of a wireless transmission apparatus.
Description of Related Art
Referring to FIG. 1, FIG. 1 is a plot of frequency response according to an input impedance and an output impedance of a prior art wireless signal transmission apparatus. The prior art wireless signal transmission apparatus has a power amplifier, and an impedance matching apparatus. The curve 110 is a response curve obtained according to an output impedance of the wireless signal transmission apparatus. The curve 120 is a response curve obtained according to the input impedance of the wireless signal transmission apparatus. It can be easily seen, in the prior art, a return loss by coupling the power amplifier 110 to the impedance matching apparatus 120 is between −4 dB to −6 dB. That is, an absolute value of the return loss is too small, and a large voltage standing wave ratio (VSWR) is induced. Such as that, a power transmission efficiency of the wireless signal transmission apparatus 100 is reduced for the large VSWR.